TODO update
core: TagDataComposite removed
core: introducing TagUpdater
core: difining behaviour of setTag(s) functions of ITagData
core: TagUpdater: initial implementation
gui: PhotosStagingArea: disabling temporarily not working code
database: IPlugin: removing redundancy of PrjData (see Database::ProjectInfo)
database: IPhotoInfo uses simpler type for tags now
core: TagDataBase & TagData removed - useless
code refactor
code refactor
database: IPhotoInfo: exclusive access to tags introduced
core: TagUpdater: using new method for exclusive access to tags
gui: StaggingArea: introducing TagGroupUpdater
fixing runtime crash
core: adding missing external visibility
gui: TagEditorWidget: removing some debug messages
code format
gui: PhotosStagingArea: implementation for getTags() and isValid(); viewSelectionChanged() refreshed
gui: TagEditorWidget: removing more debug messages